Applicants"" invention relates to a method to allocate storage elements disposed within an automated data storage and retrieval system while that system is in a reset state. Applicants"" invention further relates to a method to return the automated data storage and retrieval system to a ready state from a reset state. Applicants"" invention further relates to a method to adjust the system recovery period during which the system is in a reset state.
Automated media storage libraries are known for providing cost effective access to large quantities of stored media. Generally, media storage libraries include a large number of storage slots on which are stored portable data storage media. The typical portable data storage media is a tape cartridge, an optical cartridge, a disk cartridge, and the like. One (or more) accessor typically accesses the data storage media from the storage slots and delivers the accessed media to a data storage drive for reading and/or writing data on the accessed media. Suitable electronics both operate the accessor and operate the data storage drives to transmit to, and/or to receive data from, an attached on-line host computer system.
In a conventional automated media storage library, the storage slots are arranged in a planar orthogonal arrangement forming a xe2x80x9cwallxe2x80x9d of storage slots for holding data storage media. The plane may be a flat plane, or may be a cylindrical plane. To double the storage capacity, two xe2x80x9cwallsxe2x80x9d of storage slots may be provided on either side of the accessor.
A number of different companies manufacture automated media storage libraries today, each model displaying various different features. One example is the IBM 3494 Media Storage Library. Some of the automated media storage libraries have dual or multiple accessors to provide a level of redundancy.
The data drives located within an automated data storage and retrieval system may become contaminated with airborne particulates, storage media debris, and other foreign material. Such contaminants may disrupt the movement of media, or the head-media interface, thereby interfering with normal operations of the device. It is therefore known to clean the internal components of a device. Numerous techniques for such cleaning of devices are known in the art. For example, U.S. Pat. No. 4,384,311 discloses a magnetic disk drive including means for cleaning the magnetic heads therein. The magnetic heads are cleaned by reducing the spindle motor speed so that the heads fly at a reduced flying height relative to their normal flying height over the disks. Particles larger than such reduced flying height are thereby scrubbed off the heads. Some device cleaning techniques require the insertion of a special portable data drive cleaning device therein. Such cartridges include means particularly suited for cleaning the transducing head of a device, such as brushes or pads. Examples of portable data drive cleaning devices are disclosed in U.S. Pat. No. 4,870,636 and U.S. Pat. No. 4,817,078, all of which relate to optical disk drives, and in U.S. Pat. No. 4,594,617, which relates to magnetic disk drives.
Data drive devices can be made to signal their need to be cleaned in numerous ways. In the simplest technique, the need for cleaning is indicated when the device stops functioning, or is manually observed functioning at a level of performance below that otherwise expected. In another technique, a device is cleaned at certain intervals of time or use which are predefined from historical observations. Each of these techniques may be improved by building the capability of self-monitoring into the device. A data drive device can be made to monitor its own level of performance, or log time or usage, and signal an operator when cleaning is required via an indicator light or console.
An automated data storage and retrieval system operates in communication with one or more host computers when in a xe2x80x9cready state.xe2x80x9d In such a ready state, the host computer requests access to one or more data storage media housed in one or more portable data storage cartridges located within the system. After reading data from, and/or writing data to, the data storage media disposed within those designated portable data storage cartridges, the host computer then instructs the automated data storage and retrieval system to return those cartridges to storage.
A number of scenarios exist in which an automated data storage and retrieval system switches from a ready state to a reset state. When such a transition from a ready state to a reset state occurs, one or more on-going operations may be interrupted. For example, a cleaning device may be in transit between a storage slot and a data drive device. On the other hand, a cleaning device may be disposed within a data drive device when the system switches to a reset state. What is needed is a method to allocate storage elements disposed within an automated data storage and retrieval system while that system is in a reset state, a method to return the automated data storage and retrieval system to a ready state from a reset state, and a method to adjust the system recovery period during which the system is in a reset state.
Applicants"" invention includes a method to return an automated data storage and retrieval system from a reset state to the ready state, where the automated data storage and retrieval system includes one or more host computers, one or more data drive devices, one or more portable data drive cleaning devices, and a plurality of storage elements. In certain embodiments, Applicants"" method allocates a different storage element for each of the system""s portable cleaning devices before returning the automated data storage and retrieval system to the ready state from a reset state. Applicants"" invention further includes a data storage and retrieval system which includes a computer useable medium having computer readable program code disposed therein to implement Applicants"" method to return the automated data storage and retrieval system to the ready state from a reset state.
Applicants"" invention further includes a method to allocate storage elements disposed within an automated data storage and retrieval system while that automated data storage and retrieval system is in a reset state. Applicants"" invention further includes a data storage and retrieval system which includes a computer useable medium having computer readable program code disposed therein to implement Applicants"" method to allocate storage elements disposed within an automated data storage and retrieval system while that automated data storage and retrieval system is in a reset state.
Applicants"" invention further includes a method to adjust the system recovery period of an automated data storage and retrieval system after that system is placed in a reset state. Applicants"" invention further includes a data storage and retrieval system which includes a computer useable medium having computer readable program code disposed therein to implement Applicants"" method to adjust the system recovery period of an automated data storage and retrieval system after that system is placed in a reset state.